An organic thin film transistor (OTFT) is a logic unit element with an organic semiconductor as an active layer, and it has such advantages as being suitable for massive production, being adapted to a flexible substrate and being of low production cost, so it has been widely used in flat-panel displays, sensors, memory cards and radio frequency identification (RFID) tags. Hence, the research and development of the OTFT has attached more and more attentions.
Currently, a patterning process of a traditional OTFT is usually achieved by ink-jet printing or photolithography. However, the ink-jet printing method can merely be used to meet a scenario where a low resolution is required, and a new printing device is required to achieve the massive production. Hence, it is more suitable to adopt photolithography, with lower production cost, as the patterning process to achieve the massive production of the OTFTs.
However, when the active layer of the OTFT is manufactured by photolithography, it is at first required to apply a photoresist layer onto the active layer. Next, the photoresist layer is directly exposed and developed so as to define an active layer pattern at the photoresist layer. Then, the active layer is etched by using the defined active layer pattern as a mask, so as to form the active layer pattern. Finally, the remaining photoresist at the active layer is removed, so as to form the active layer. During the manufacture of the active layer, the photoresist layer is in direct contact with the active layer, so the active layer will be damaged when removing the remaining photoresist on the active layer, thereby the performance of the OTFT will be adversely affected.